The developing human central nervous system consists of pluripotent cells which mature in astrocytes, oligodendrocytes and neurons . We have been examining human fetal brain tissue from gestational ages ranging from 8 weeks to 22 weeks inclusive to determine at which gestational ages each of these differentiated cells can be identified. The constituent elements of the developing central nervous system can be separated from one another by mechanical methods allowing study of individual cellular components. This also allows the production of highly purified cultures of fetal neurons or astrocytes which can be used in cell culture models for HIV-1 or other neurotropic infections. These brain cell cultures can also be useful in testing transplantation protocols for therapy of neurodegenerative disorders. We have previously developed an immortalized human fetal astrocyte line (SVG) and have implanted the cells into rat brain. We have also further modified these cells by insertion of a tyrosine hydroxylase gene construct which is amplified by replication of its ORI sequences using the constitutively expressed SV40 T protein. These cells, SVG-TH, could potentially serve as an alternative to neural grafts of primary tissue in transplantation studies.